Orenstein N S, Buczynski A, Dvorak H F
Cancer Res. 1983 Apr;43(4):1783-9.
Line 10 guinea pig carcinoma cells cultured in serum-free medium for 4 hr elaborate plasminogen activator (PA) activity that remained in the supernatant after ultracentrifugation (100,000 X g, 90 min). PA activity in line 10 conditioned medium occurred in both active and cryptic forms. The vast majority of active PA adsorbed to lysine-Sepharose and could be eluted at low pH as several activities that electrophoresed in the Mr 50,000 to 80,000 range on nonreduced sodium dodecyl sulfate-polyacrylamide gel electrophoresis. A small amount of active PA, running in the Mr 50,000 to 60,000 region, and cryptic PA did not adhere to lysine-Sepharose. Treatment of lysine-Sepharose-nonadherent fractions with catalytic amounts of plasmin or trypsin induced substantial new PA activity that adsorbed to lysine-Sepharose, bound [3H]diisopropylfluorophosphate, and that electrophoresed as several bands of activity with molecular weights from 50,000 to greater than 100,000 on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Of additional interest, the amount of active PA measured in conditioned medium was substantially increased when certain protease inhibitors, tranexamic acid, epsilon-aminocaproic acid, or Trasylol, were included during culture.
在无血清培养基中培养4小时的10号线豚鼠癌细胞可产生纤溶酶原激活物（PA）活性，该活性在超速离心（100,000×g，90分钟）后仍保留在上清液中。10号线条件培养基中的PA活性以活性形式和潜在形式存在。绝大多数活性PA吸附到赖氨酸-琼脂糖上，并可在低pH下洗脱，表现为几种在非还原十二烷基硫酸钠-聚丙烯酰胺凝胶电泳上迁移率在Mr 50,000至80,000范围内的活性。少量在Mr 50,000至60,000区域迁移的活性PA和潜在PA不粘附于赖氨酸-琼脂糖。用催化量的纤溶酶或胰蛋白酶处理赖氨酸-琼脂糖非粘附部分可诱导大量新的PA活性，该活性吸附到赖氨酸-琼脂糖上，结合[3H]二异丙基氟磷酸，并在十二烷基硫酸钠-聚丙烯酰胺凝胶电泳上表现为几条活性带，分子量从50,000到大于100,000。另外有趣的是，当在培养过程中加入某些蛋白酶抑制剂，如氨甲环酸、ε-氨基己酸或抑肽酶时，条件培养基中测得的活性PA量会显著增加。
